Heat and light sensitive diazo sulfonate and azo coupler coated sheet



United States Patent 3,312,551 HEAT AND LIGHT SENSITIVE DIAZO SULFO- NATE AND AZO COUPLER COATED SHEET Oskar Siis, Wiesbaden-Biebrich, Germany, assignor, by

mesne assignments, to Keulfel 8: Esser Company, Hoboken, N .J. No Drawing. Filed July 24, 1963, Ser. No. 297,235 Claims priority, application Germany, July 25, 1962, K 47,332; Get. 5, 1962, K 47,898 21 Claims. (Cl. 96-75) The present invention relates to reflex thermography and more particular relates to a thermographic reflex process and to materials for use in said process.

Light sensitive derivatives of diazo compounds which are not capable of coupling, but which are converted into diazo compounds that subsequent-1y are capable of coupling by heating are known. Examples of such disguised or protected diazo compounds are the diazo sulfonates which have been utilized in two-component diazotype reproduction materials. These diazo sulfonates are coated together with an azo component for development after image formation by heating. The sulfonates are used in the form of metal salts, in particular the alkali metal salts. Opaque paper is used as supporting material.

Furthermore, a thermographic reflex process which uses an aryldiazo sulfone as the heat sensitive compound is known. The thermographic reflex copies obtained according to this process can be fixed by the influence of light. However, the heat sensitivity of the sulfones is relatively low.

Now a process for the preparation of reflex copies by imagewise heat exposure and uniform light exposure has been found. The process is distinguished by its high copying speed and good contrast. The process makes use of copying material comprising a transparent base bearing a light sensitive layer containing at least one diazo sulfonate of the formula:

R and R each represent an alkyl group having from 1 to carbon atoms, or R and R taken together with the nitrogen atom to which they are bonded, form a heterocyclic ring which may be substituted by one or more alkyl groups; and where R stands for hydrogen, alkyl or alkoxy group;

R stands for alkyl or alkoxy group; and

Ka stands for the cation of an organic amino compound.

Materials with the best storage properties are those containing diazo sulfonates where R and R stand for alkyl with one to three carbon atoms, particularly methyl or ethyl groups, or where R and R form part of a heterocyclic group, such as the piperidino, morpholino, piperazino, pyrrolidino or tetrahydroquinolino groups, which may be substituted, e.g. by the Z-methyl or 2-ethylmorpholino groups, 2,3-dimethyl-rnorpholino-2, 5-dimethyl-- morpholino, 2,6-dimethylam0rpholino, 3,5-dimethyl-morpholino, 5-methyl-2-ethyl-morpholino, S-methyl-S-ethylrnorph-olino, 2,6-diethylmorpholino or 2,3,5-trimethylmorpholino groups. Diazo sulfonates where R and R represent alkyl with 4 or 5 carbon atoms, can also be used according to the present invention.

The light sensitive layer can also contain at least one natural or synthetic resin which is soluble in organic. solvents and has a softening point in the range of from 70 to 200 C., and at least one azo component exhibiting keto-enol-tautomerism.

ICC

Diazo sulfonates having an organic .base as a cation instead of the conventional inorganic cation were found to be most successfully applied to the present thermographic reflex process.

Therefore one object of the present invention is to provide methods and materials of utilizing diazo sulfonates having an organic base cation for a thermographic reflex process which has high copying speed, good contrast, and good shelf-life.

Other objects will become apparent during the course of the specification.

By appropriate selection of the organic base, diazo sulf-onates of varying heat sensitivity can be prepared, so that the process of the present invention can be adapted to the requirements of each case. Among the organic bases of the aliphatic series are amines having alkyl radicals with more than three carbon atoms in the alkyl groups. These radicals have proved most suitable as cations for the diazo sulfones to be used according to the present invention. Among the amines of the aromatic series, those of higher molecular weight are best suited, e.g. benzidine, amino fluorene, amino chrysene, amino carbazole, and substituted aromatic amines such as 1- amino-2,5-diethoxy-4-benzoylamino-benzene. Some of the diazo sulfonates suitable for the present invention are scarcely soluble in solvents. Poor solubility, however is no bar for their use according to the present invention, since the diazo sulfonates may also be applied to the support as a dispersion in organic solvents or in water. These coating dispersions are also stable for a long time and, when coated onto a support, yield a heatsensitive material of good shelf-life.

The compounds with the organic cation can be prepared from the alkali salt of the diazo sulfonates by adding the hydrochloride of the organic base to the aqueous solution of the alkali salt. Since the diazo sulfonates with organic cations are less soluble in water than the corresponding alkali salts, they precipitate from the aqueous solutions. In many cases, however, they are readily soluble in organic solvents. A detailed description of the preparation of these compounds is given in the second of the following examples.

Azo components which may be used according to the present invention are phenols or naphthols having more than one hydroxy group linked to the phenol or naphthol nucleus, aceto acetic ester derivatives, pyrazolones and dihydro-resorcinols. Examples are phloroglucinol, acetoacetic amide and dihydro-resorcinol, e.g. 5,5-dimethylcyc-lohexandione-l,3.

For the preparation of the heat senstive layers suited for the copying process, papers transparent to infrared radiation or heat rays vare coated in known manner with the two components, in the form of solutions or dispersions in organic solvents or in water.

Resins can be added to the solutions or dispersions of the diazo sulfonates. These resins immobilize the diazo sulfonates and the azo components at room temperature and permit color formation only under the influence of heat. Suitable resins are higher molecular products having softening points in the range of 70 to 200 C., preferably from to C. Organic solvent soluble polycondensates of adipic acid with diamines and polyamides of the nylon-type are preferably used. Other resin which can be used according to the present invention with great success are polyacrylic acid esters and amides, and ethyl cellulose. The addition of a resin causes a considerable improvement of the shelf life of the coated material, as compared with a corresponding material having no resin added.

The resins are insoluble in water, but soluble in organic solvents, and they are preferably applied to the support heat rays.

Directly readable, unreversed copies are obtained when the imageis produced on the surface of the reproduction material which is away from the original, so that the surface of the reproduction material which carries the copying layer is turned to the heat radiator. In this modification of the process, the transparent paper used for the copying layer should advantageously have a thickness of from about to about 100 microns, preferably from about to about 60 microns. In one modification of the present invention, the back of the support is provided with a covering layer, by which the image pro duced is covered from the back and is thus rendered invisible or virtually invisible. Such covering layers consist of a binder, such as ethyl cellulose, and a pigment, such as titanium dioxide, zinc oxide, lithopone or baryta white.

The copies produced by the reflex process are fixed by bleaching the diazo sulfonate by the action of light. This can be effected by means of artificial light sources or by exposure to full daylight.

The new process is distinguished from known processes in which reproduction by reflected heat and fixation by exposureto light are combined by its increased speed of operation and better reproduction of contrasts. The shelf-life of these papers is also superior to that of known heat-produced and light-fixed materials.

In the following examples percentages are by weight.

Table I following the examples contains the formulas of the diazo sulfonates mentioned in the examples. The temperatures stated indicate the melting points and dec. indicates with decomposition.

" Example 1 A support of infrared transparent paper was coated on one surface with a suspension comprising:

Ethyl cellulose grams 16.7 Titanium dioxide do 66.7 Acetone ml 1000 to form a pigment layer on one side of the support. The unpigmented side of the support was then coated with a solution comprising:

Phloroglucinol grams 4.0 Thiourea do 12.5 Sodium 1-rnethoxynaphthalene-4-sulfate do 8.5 Sodium salicylate do 5.0 Ultramid 1 C (commercial name of a mixed condensate of adipic acid hexamethylene diamine and caprolactam) grams 10.0 Methanol ml 500.0

Immediately preceding the coating step, 7.5 grams of the di-n-butylamine salt of 1-diaZo-4-diethylamino-Z-ethoxybenzene-sulfonate corresponding to Formula 1 were added to this solution.

The paper thus prepared was dried at a temperature not exceeding 60 C.

'Reflex copies were prepared in a commercially available thermographic reproduction apparatus as follows:

The original, which could have graphic intelligence on one or both sides, was placed in heat conductive relation with the copying material in such a manner that the surface coated with the pigment layer was in contact with the surface of the original carrying the image to be produced. Original and copying material were then introduced into an apparatus in such a way that the heat rays passed through the copying material before reaching the original. From there, they were selectively reflected or transmitted by the image on the original. From an original, a dark blue, right-reading copy on a yellow background was thus obtained in 2 to 4 seconds.

To fix the image, the copy was exposed without the original to one of the light sources customary in the reproduction field or to daylight. The yellow background bleached out, and the copy was thus fixed.

Example 2 A tissue paper (single use carbon paper base) was coated with a diazo sulfonate solution. Instead of the di-butylamine salt of the diazo sulfonate used in Example 1, the diazo sulfonate was the mono-methylamine cation salt of said compound (Formula 2), but the solution was otherwise identical to that used in Example 1. The support was not provided with a pigment layer.

For the preparation of copies, the coated side of the paper was placed in contact with the image to be reproduced, and both reproduction material and original were thus introduced into a heat-developing apparatus. Reversed, strongly blue-colored reflex copies were thus obtained which, due to the good transparency of the raw paper used, appeared right-reading from the back.

Fixation of the copy was effected as in Example 1.

Instead of the mono-methylamine salt of 1-diazo-4- diethylamino-2-ethoxybenzene-sulfonate (Formula 2), the

(Formula 6), the piperazine salt (Formula 7), the aniline salt (Formula 8), the l-amino-Z-naphthol-ethyl ether salt (Formula 9), and the 4,4-diamino-2,2-dihydr0xydiphenyl salt (Formula 10).

The compound corresponding to Formula 2 was prepared as follows: 6.5 parts by weight of 1-diazo-4-diethylamino-Z-ethoxy-benzene sulfonate (Na-salt) were dissolved in 30 parts by volume of water. A solution of 12. parts by weight of methylamine (HCl-salt) in 20 parts by volume of water was added to the solution. Upon stirring with a glass rod, crystallization set in and ended after about 15 minutes. The sulfonate was obtained in the form of yellow crystals which were separated by suction and recrystallized from about 40 ml. of ethanol. The salt thus obtained was readily soluble in water and melted at 154 C. with decomposition.

The compounds corresponding to Formulas 1 and 3 to 10 were prepared analogously. Starting material is the sodium salt of the 1diazo-4-diethylamine-2-ethoxybenzene sulfonate, to which the hydrochloride of the amine in question was added in aqueous solution.

Example 3 The di-n-butylamine salt of 1-diazo-4-diethylamine-2- ethoxybenzene sulfonate (Formula 1) used in Example 1 was applied to a thin printing paper in a 2.7 percent solution in acetone, which solution contained in addition:

with strong blue lines and a pure white back were pro-- duced. The raw paper appeared opaque to the naked eye, but it is sufficiently transparent to heat rays that reflex copies can be prepared. Fixation was effected as in Example 1, by exposure of the yellow background to the; light of a customary light source.

It is advantageous when such raw paper is used that no image appear on the reverse side.

was finely ground, made up with di-iso-propylether to 1500 ml., and then coated onto transparent paper. Reflex copies were prepared from the paper thus treated as described in the preceding examples.

Instead of the above mentioned diazo sulfonate, those corresponding to Fonmulas 11, 12, 13, 14, or were used with equally good results.

Formula 1 H5 0 2NC 2H5 Like Formula 1 69 [K8;=CH3NH3 154 dec.]

Formula 3 Like Formula 1 G9 [K8.=CgH5-NH3 138 dec.]

Formula 4 Like Formula Formula 5 Like Formula 1 63 l =(CzH5)zNH2 139 dec.]

Formula 6 Like Formula 1 KFOCHzNH! 142 dec.

Formula 7 Like Formula 1 131 dec.

Formula 8 Like Formula 1 133 dec.

Formula 9 Like Formula 1 G) N H 139 dec.

Formula 10 Like Formula 1 HO OH 89 dec.

Formula 11 138 dec.

Formula 1'2 O (C 2)aC a 113 dec.

Formula 13 (CHaCHzCHflzN NnSO3NHaC5I-I5 O C2H5 146 dec.

Formula 14.-

- dec.

Formula 15 O CzHlS 119 dec.

What is claimed is:

1. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising an azo compound and a diazo sulfonate salt sensitive to heat and light, said diazo sulfonate having the formula where R and R are members selected from the groups consisting of:

group A wherein R and R are alkyl groups having from 1 to 5 carbon atoms and group B wherein R and R are members of a heterocyelic ring, R is a member selected from the group consisting of:

hydrogen, alkyl, and alkoxy,

R is a member selected from the group consisting of alkyl and alkoxy, and

Ka is a cation of an organic ammonium compound.

2. A reproduction material in accordance with claim 1 in which said diazo sulfonate salt is selected from the group consisting of: dibutylamine salt of 1-diazo-4-diethylamino 2 ethoxybenzene sulfonate; mono-methyl amine salt of 1-diazo-4-diethylamino-Z-ethoxybenzene sulfonate; mono-ethylamine salt of 1-diazo-4-diethylamino-Z-ethoxybenzene sulfonate; dimethylamine salt of l-diazo-4-diethylamino-Z-ethoxybenzene sulfonate; diethylamine salt of 1-diazo-4-diethylamino-2-ethoxybenzene-sulfonate; monobenzyl amine salt of 1-diazo-4- diethylamino-2-ethoxybenzene sulfonate; piperazine salt of 1 diazo-4-diethylamino-2-ethoxybenzene sulfonate; aniline salt of 1-diazo-4-diethylamino-Z-ethoxybenzene sulfonate; 2-ethoxy-1-naphthylamine salt of l-diazo 4- diethylamino-Z-ethoxybenzene sulfonate; 2,2'-dihydroxy- 4,4 diamino-biphenyl half salt of 1-diazo-4-diethylamino- 2-ethoxybenzene sulfonate; aniline salt of l-diazo-2,5- diethoxy-4 morpholino-benzene sulfonate; aniline salt of 1 diazo-2,5-dibutoxy-4-morpholino-benzene sulfonate; aniline salt of 1-diaz0-2-ethoxy-4-dipropylamino benzene sulfonate; octadecylamine salt of 1-diazo-2-ethoxy-4-diethylamino-benzene sulfonate; and l-diazo-2-ethoxy-4-diethylamino benzene sulfonate double salt of 4,4-diaminodiphenyl-ketone.

3. A reproduction material in accordance with claim 1 in which said azo component is a member selected from the group consisting of: polyhydroxy benzenes, polyhydroxy naphthalenes, aceto acetic amide derivatives, pyrazolones, and dialkyl cyclohexanediones.

4. A reproduction material in accordance with claim 1 in which said azo component is a member selected from the group consisting of: phloroglucinol, acetoacetic amide and 5,5-dimethylcyclohexanedione-1,3.

5. A reproduction material in accordance with claim 1 in which said heat-sensitive layer comprises a resin soluble in organic solvents and softening in the range of 70 to 200 C., said-resin being a member selected from the group consisting of polycondensates of adipic .acid hexamethylene diamines and caprolaotam, polyacrylic acid esters, polyacrylic acid amides, and ethyl cellulose.

6. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the mono-methylamine salt of 1-diazo-4-diethylamino-2- ethoxy-benzene-sulfonate.

7. A reproduction material for a thermographic reflex process comp-rising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the ethyl amine salt of 1-diazo-4-diethylamino-Z-ethoxybenzene-sulfonate.

8. A reproduction material for a thermograhic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the dirnethylamine salt of 1-diazo-4-diethylarnino-2- ethoxy-benzene-sulfonate.

9. A reproduction material for a therrnographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the diethylamine salt of 1 diazo-4-diethylamino-Z-ethoxybenzene-sulfonate.

10. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the benzylamine salt of 1-diazo-4-diethylamino-2- ethoxy-benzene-sulfonate.

11. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the piperazine salt of 1-diazo-4-diethylamino-Z-ethoxybenzene-sulfonate.

12. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the aniline salt of l-diazo-4-diethylamino-2-ethoxy-ben- Zene-sulfonate.

13. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the 1-amino-2-naphthol-ethyl ether salt of l-diazo- 4-diethylamino-Z-ethoxy-benzene-sulfonate.

14. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising mixed condensate of adipic acid hexamethylene diamine and caprolactam, phloroglucinol and the 4,4'-diamino-2,2'-dihydroxy-diphenyl salt of l-diazo- 4-diethylamino-2-ethoxy-benzene-sulfonate.

15. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising ethyl cellulose, phloroglucinol and din-butylamine salt of 1-diazo-4-diethylamino-2-ethoxy benzene-sulfonate.

16. A reproduction material for a therrnographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising ethyl cellulose, phloroglucinol and aniline salt of 1-diazo-4-diethylamino-2-ethoxy-benzenesulfonate.

17. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising ethyl cellulose, phloroglucinol and aniline salt of 1-diazo-2,5-diethoxy-4-morpholino-benzenesulfonate.

18. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising ethyl cellulose, phloroglucinol and aniline salt of l-diazo 2,5-dibutoxy-4-morpholino-benzenesulfonate.

19. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on said support, said layer comprising ethyl cellulose, phloroglucinol and aniline salt of 1-diazo-2-ethoxy-4-dipropylamino-benzene-sulfonate.

20. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on support, said layer comprising ethyl cellulose, phloroglucinol and octadecylamine salt of 1-diazo-2-ethoxy-4-diethylaminobenzene-sulfonate.

21. A reproduction material for a thermographic reflex process comprising a support transparent to heat rays and a heat-sensitive layer coated on support, said layer comprising ethyl cellulose, phloroglucinol and 1-diazo-2-ethoxy-4-diethylamino-benzene-sulfonate double salt of 4,4'-diamin0-diphenyl ketone.

References Cited by the Examiner STATES PATENTS Sus 96-91 Sorensen 11736.8 Coles et a1. 117-36.8

10 3,135,607 6/1964 Hills 11736.8 3,175,906 3/1965 Sus et al. 9691 3,199,982 10/1965 Kashiwabara 96-91 OTHER REFERENCES Kosa-r: Photographic Sci. and Eng., vol. 5, No. 4, July-August 1961, pp. 239-243, especially 243.

MURRAY KATZ, Primary Examiner. 

1. A REPRODUCTION MATERIAL FOR A THERMOGRAPHIC REFLEX PROCESS COMPRISING A SUPPORT TRANSPARENT TO HEAT RAYS AND A HEAT-SENSITIVE LAYER COATED ON SAID SUPPORT, SAID LAYER COMPRISING AN AZO COMPOUND AND A DIAZO SULFONATE SALT SENSITIVE TO HEAT AND LIGHT, SAID DIAZO SULFONATE HAVING THE FORMULA 